The present invention relates to a transfer device for goods delivered on a first conveyor device, particularly cans, for instance aluminum cans, which are transferred in groups in the direction of conveyance of the first conveyor device, from the first conveyor device to a second conveyor device, the depositing of the goods onto the second conveyor device taking place in the manner that said row extends transverse to its direction of conveyance, having a receiving device which holds the corresponding group of goods upon the transfer and is guided by at least one drive along a path of movement, the receiving device being a suction beam which is connected by a switch device to a source of vacuum, the switch member of which device is brought into vacuum connect or a vacuum disconnect position as a function of the position of the suction beam.
The first conveyor device can, for instance, be a first belt on which the goods are arranged in a row (in particular in one row, or also in two or more rows alongside of each other). The transfer device receives a section, and therefore a group of the goods from this row or each of these rows, and transfers it to the second conveyor device, where the goods are deposited. The depositing is effected with such an alignment of the row or rows that the lengthwise direction of the row or rows is transverse to the direction of conveyance of the second conveyor device. When the second conveyor device for instance also is a belt, then the row of goods extends transverse and particularly perpendicular, to the longitudinal direction of the belt. The goods may, for instance be cans and, in particular beverage cans, which are printed on on their outer side one after the other in a printing machine arranged in front of the first conveyor device and then conducted by the conveyor device to the transfer device. The transfer device rearranges the cans which have been received in groups in such a manner that they are deposited on the second conveyor device in, in each case, rows extending parallel to each other, the lengthwise direction of these rows being transverse to the direction of conveyance of the second conveyor device. In this way, the second conveyor device is provided very compactly with goods which--in the case of the aforementioned cans--are, for instance, fed to a drying device (continuous drying device). The transfer device is so developed that by means of its receiving device it receives goods from the first conveyor device, it moving along in synchronism with the goods during the receiving process so that there is only a slight relative movement, if any, between the goods and the receiving device during the receiving process. This assures a taking over in correct position and therefore a reliable taking over even in the case of high speeds. The same is true of the process of depositing on the second conveyor device. Here also, the receiving device moves in a fixed movement-path region synchronously, or almost synchronously, with the conveyor means of the second conveyor device so that a depositing in precise position is possible without the goods striking against each other or falling over, etc. Since the transfer process must be carried out very rapidly due to the large number of goods delivered, it is necessary to hold the goods very firmly on the receiving device during the transfer process due to the forces of acceleration which occur. For this purpose, the receiving device is developed as a suction beam, that is vacuum holding is employed. The goods are drawn up from above and then transferred. For this, it is not necessary that the receiving device change its vertical position but, rather, it can move in a plane. If it is a slight distance above the upper edges of the cans during the reception, this is sufficient for a suction process. The same applies to the depositing, the depositing process being brought about in the manner that the vacuum is disconnected and in this way the goods are released and deposited onto the second conveyor device.
A transfer device of the type described above can be noted from European Patent Application 0 563 461. This known transfer device has a switch device for the connecting and disconnecting of the vacuum, it being connected to a source of vacuum, the switch member of the switch device being actuated as a function of the position of the suction beam. The switch member is developed as a pusher which is moved back and forth via a crank drive which is coupled to a shaft of the drive means of the transfer device, as a result of which the vacuum is connected and disconnected. By means of corresponding mechanical displacement members, the switching device can be so adjusted upon the placing in operation of the transfer device that the suction action on the goods takes place at the correct time and furthermore the depositing of the goods takes place in the suitable position of the suction beam. Since dead times must be taken into account for the building up of the vacuum as well as for the reduction of the vacuum, and furthermore there is a switch time for the switching device and also other operating parameters exert an influence, the mechanical switch means of the prior art must be developed as so-called phase displacement mechanism since certain operating parameters, such as, for instance, the speed with which the transfer device operates, have an influence on the time delay until the time of production of the suction and the time of depositing of the goods. This means that, upon the starting of the transfer device or upon operation with low speed, a corresponding control of the switch member must take place in order that the goods are properly transferred. If an increase in the operating speed of the transfer device takes place, for instance to the maximum value, then the phase displacement mechanism must also be displaced in corresponding manner. This means an expensive construction which requires adjustments in operation and furthermore needs improvement with respect to its accuracy. Furthermore, the known mechanical displacement upon a transfer to, for instance, other cans always results in the difficulty that not only the phase displacement mechanism but also mechanical couplings to the switch member must be displaced, which requires very expensive adjustment work.